1. Field of the Invention
The present invention relates to an imaging system, and in particular relates to an imaging system comprising a photographic apparatus for causing a photographic light source to emit light momentarily via the operation of a shutter button to photograph a fundus of an eye to be examined a preset number of times.
2. Description of the Prior Art
One type of ophthalmologic examination that has conventionally been performed involves strobe light being emitted, whereby a fundus is imaged using a fundus camera comprising a CCD or other imaging device, and the resulting fundus image is captured as an image signal in a computer or another image capturing device.
FIG. 18a shows an example of such an imaging system. In a fundus camera 100, a trigger signal generating button is pressed, whereby a trigger signal S1 is generated, and, based on the trigger signal, an image capturing device 101 generates a strobe signal S2 for the fundus camera 100 and an imaging device 102. On receiving the strobe signal S2, the fundus camera 100 generates strobe light and drives an internal optical component, and the imaging device 102 produces an image obtained from the optical system of the fundus camera. The image produced in the imaging device 102 is captured as an image signal in the image capturing device 101, and is then processed, recorded, and saved as required.
Meanwhile, once the trigger signal has been generated, the fundus camera 100 generates a trigger mask signal S11 for keeping the trigger signal from being generated for a fixed period of time, and a strobe mask signal S12 for keeping the emission of strobe light or another photographic operation prompted by the strobe signal from being performed multiple times, and these signals are employed in the above-described operation. A method also exists wherein a strobe-enabling signal rather than the strobe mask signal is generated and employed.
In an example of a conventional system shown in FIG. 18a, the image capturing device 101 or another external device is invariably necessary. However, in the example of a system shown in FIG. 18b, an external device is not strictly necessary, the fundus camera 100 generates a trigger signal S1 to the imaging device 102, and the imaging device 102 generates a strobe signal S2 to the fundus camera 100 simultaneously on receipt of the signal S1 or when otherwise suitable for image capture. On receiving the strobe signal S2, the fundus camera 100 then generates strobe light or performs another action in the same manner as in the example of the system shown in FIG. 18a. In FIG. 18b, the imaging device 102 and image capturing device 101 are shown in a connected state. However, the image capturing device 101 is not strictly necessary when a memory device is incorporated in the imaging device 102.
Traditionally, stereophotography is used to provide two images having a parallax from the same fundus, and these images are displayed as a pair, whereby the fundus can be viewed stereoscopically. A fundus camera able to capture such stereo images having a parallax is provided with a photographic stop in which right and left apertures are formed (two-aperture stop). In accordance with the shutter operation, an image is captured from one aperture of the photographic stop and then from the other aperture, strobe light is generated for each, and two images for stereoscopic viewing are obtained in succession (see Japanese Laid-open patent application 1984-90547)
In a conventional system, the capturing of two stereo images having parallax necessarily involves operating a trigger signal generating button (or the like) at least twice, and causing the strobes to be emitted in succession. A problem arises in that an opportunity to obtain a favorable stereo image will be lost due to slow operation of the shutter.
It is therefore an object of the invention to provide an imaging system being capable of controlling a photographic operation in which a light source is caused to emit light a preset number of times and capable of providing a favorable image for each photography.